LINE X TESTER ANALYSIS FOR YIELD COMPONENTS AND FIBER PROPERTIES IN SOME COTTON CROSSES OF (Gossypium barbadense L.)

Abstract

The present study was carried out at Sakha Agricultural Research Station, Cotton Research Institute, Agricultural Research Center, Egypt, during 2017 and 2018 seasons. This investigation was carried out to estimate heterosis, combining ability, proportional contributions, genetic components and heritability estimates of some characters for six Egyptian cotton varieties as lines i.e, Giza 90, Giza 95, Giza 86, Giza 94, Giza 92 and Giza 96, while, the other five genotypes used as testers were Karshenky, Suvin, Australy 13, Pima S7 and Pima S6, using line x tester analysis. In 2018 season a randomized complete blocks design with three replications was carried to evaluate all genotype (eleven parents and their 30 F1s crosses) for some genetic parameters. The results indicated that mean squares due to the genotypes, parents, crosses and parents vs. crosses were significant and highly significant for all traits studied, except No. of bolls/plant in the parents, lint percentage in the crosses and fiber strength in the crosses and parents vs. crosses. The mean squares due to lines were significant for all studied traits. Mean square for testers and Line x Tester were significant for most traits studied. The following crosses demonstrated the best heterosis relative to midand better-parent, i.e, Giza 95 x Karshenky, Giza 95 x Australy 13 and Giza 95 x Pima S7 for most traits studied, while the following crosses demonstrated the best heterosis relative to midand better-parent for most studied yield traits, i.e. Giza 90 x Australy 13 and Giza 86 x Karshenky. The crosses Giza 92 x Karshenky, Giza 92 x Australy 13, Giza 92 x Pima S7, Giza 96 x Suvin and Giza 96 x Pima S7 were the best heterosis relative to mid-parent for most studied fiber traits. The results revealed that the line Giza 95 was significant and positive desirable GCA effects for all yield traits. Giza 92 had significant and positive desirable GCA effects for seed index and fiber strength and negative desirable for micronaire reading Giza 96 had significant and positive desirable GCA effects for fiber strength and negative desirable for micronaire reading. In this respect, the results of testers showed that Australy13 had significant and positive desirable for No. of bolls/plant, seed cotton yield/plant and lint cotton yield/plant. However, estimates of specific combining ability (SCA) effects for the crosses Giza 90 x Karshenky, Giza 95 x Pima S7, Giza 92 x Karshenky and Giza 96 x Suvin were significant desirable SCA effects for some yield traits. Proportion contribution of testers contribution was higher than lines contribution for all traits studied except No. of bolls/plant. However proportion contribution of lines x testers interaction was higher than of lines and testers for most traits studied. The non-additive of genetic parameters were larger than additive genetic variance with respect to all studied traits. Broad sense heritability (h 2 b%) estimates were larger than the corresponding values of narrow sense heritability (h 2 n%) for all traits studied. The highest broad sense heritability estimates was observed in case of lint percentage with values of 71.70% and the lowest was for uniformity index with value of 27.55%, while for narrow sense heritability, it ranged from zero to 4.37% for boll weight and lint index, respectively. Generally, Giza 95 and Australy13 could be used in breeding programs for improving high yielding varieties, while Giza 92 and Giza 96 could be Y.I.M. AL-Hibbiny, et al., 506 considered as excellent parents for breeding programs to produce new varieties characterized with best fiber properties.